Why did I get a DNF in a race?

How do I exit from an activity? How do I exit the game? How do I know how far I have gone in an activity? What is the timer in the upper right corner in an activity? What are these points I see popping up on my screen? Sometimes I see a message pop up on the bottom right of my screen. Can I change the camera view in an activity? How can I tell who is in the game with me? What does the Gap mean in the Nearby Riders List? Why am I crashing? and 13 more ...